Light sources are commonly arranged on a conventional terminal block for indicating electrical connection status of the terminal block. In general, the terminal block includes a circuit board and an insulation base arranged on the circuit board, coupling openings are defined on the insulation base. In order to arrange the lights adjacent to the respective coupling openings for indicating electrical connection status of the corresponding coupling opening, a light source and corresponding light guiding structures are commonly disposed on the circuit board, and the light guiding structures extending to the respective corresponding coupling openings are arranged on the insulation base. When the insulation base is assembled onto the circuit board, light guiding structures on the circuit board are connected to the respective corresponding light guiding structures on the insulation base, and the light source is thereby guided to the respective coupling opening.
However, a large part of space in the terminal block is occupied by the terminal block light guiding structures although the light guiding structures are not big, because the terminal block is tiny. Therefore, a volume of the terminal block is difficult to be decreased.
In views of this, in order to solve the above disadvantage, the present inventor studied related technology and provided a reasonable and effective solution in the present disclosure.